Fossil fuels are a major source of energy today. They are used to generate heat and electricity and are the source materials for transportation fuels. Fossil fuels also serve as raw materials for various hydrocarbons and their derived products essential to our everyday life. Combustion of fossil fuel, however, produces carbon dioxide that contributes to global warming adversely affecting the environment. In addition, fossil fuel reserves are on a decline.
As an alternative to the declining reserves of fossil fuels, the use of methanol as a raw material for producing synthetic hydrocarbons and fuels has been suggested. Carbon dioxide has also been suggested as an alternative source of raw material (see, e.g., U.S. Pat. No. 5,928,806). It would be highly advantageous to utilize carbon dioxide, considering its virtually inexhaustible supply particularly if it could be economically captured and recycled from the atmosphere.
Carbon dioxide is present in high concentrations in the flue gases of fossil fuel-burning power plants and other various industrial exhausts. It also frequently accompanies natural gas. Many natural gas sources contain significant amounts (as much as 50% or more) of carbon dioxide. To mitigate carbon dioxide emissions and their adverse effects on the global climate, it considered to capture carbon dioxide from industrial exhausts and sequester the captured carbon dioxide in subterranean cavities or under the sea. However, sequestration does not provide a permanent solution because of its high cost and a potential for carbon dioxide leakage. Carbon dioxide is volatile and can eventually leak into the atmosphere. Inadvertent leaks of carbon dioxide can be greatly accelerated by earthquakes or other natural phenomena, and would have a catastrophic impact.
Furthermore, while it is of critical importance to curtail carbon dioxide emissions into the atmosphere, recent studies suggest that this alone will not be sufficient to reverse the damage that has already occurred. Thus, in addition to having a method for safely disposing carbon dioxide so that it does not enter the atmosphere, it would be of great benefit to also be able to remove carbon dioxide from the atmosphere to more quickly reverse the problem of carbon dioxide buildup in the atmosphere. It also would be beneficial to conduct chemical recycling of atmospheric carbon dioxide as this would provide an inexhaustible carbon source for producing fuels and synthetic hydrocarbons while at the same time mitigating global climate change that is caused or affected by the increase of carbon dioxide in the atmosphere.